Split the difference
Katherine Jeffrey is a keen supporter of single-sex schools, particularly at secondary level. The head of New Hall, an independent Roman Catholic girls' school in Chelmsford, Essex, says: "During adolescence, girls are roughly two years ahead of boys, meaning they have different needs at different stages. It's very demanding for teachers to differentiate accordingly. Girls, in particular, have a much higher chance of flourishing in a single-sex environment."
As the adolescent hormones kick in, flirting with the school heart-throb can seem far more important than periodic tables or Pythagoras' theorem.
But Lynda Wybar, head of Tunbridge Wells grammar school for girls, says that is not the only reason why teenagers benefit from single-sex education.
"It's less to do with sexual distraction than differing learning styles," she says. "Girls are far more confident and willing to take risks when there are no boys to mock or challenge their ideas. On the flip side, boys are more willing to explore sensitive issues when there are no girls to feel embarrassed in front of."
In a mixed environment, teachers are not only faced with the challenge of differentiation according to ability and learning styles - they also have to cope with gender differences.
Girls are generally better at sustained tasks that are open-ended, process-based, related to real situations and need pupils to think for themselves. On the other hand, boys are better at traditional learning styles: memorising facts and rules that have to be acquired quickly.
In that case, devising activities that meet the needs of all students can be an exhausting and almost impossible task. Attitudes to learning also differ tremendously between the sexes, and girls consistently outperform boys.
Latest figures show that 10 per cent more girls than boys gained five or more top-grade GCSEs in 2003. More than 6 per cent of boys leave school with no GCSEs, and boys are five times more likely to be excluded from school.
And social stereotypes play their part. For many boys, academic achievement is far from "cool". Those who shine are often ostracised and labelled as "geeks" or "swots". That can have adverse effects on behaviour and performance.
In a single-sex school, teachers can tailor tasks to suit boys' learning preferences, which can have a big impact on motivation, says James Fothergill, a science teacher at Gravesend grammar, a boys' school in Kent.
"Boys will always mess around," he says. "And they are more openly confrontational. But in a male environment, you can tailor your teaching more closely to their interests: many thrive on the competitive spirit."
But teaching in a single-sex school isn't without its challenges, as Mr Fothergill - who previously worked in an all- girls school - has found.
"Girls are generally more hard-working than boys - even the least able - and they usually care about presentation. But you have to adopt a completely different approach to classroom management.
"You can't raise your voice in the slightest as they'll often cry. And if you've 'had words' with a girl, she's much more likely to hold it against you, whereas boys will often 'take it on the chin' and will be fine the next time you see them."
Kevin Hogan, who used to teach in a girls' school but is now headteacher of St Matthew's RC school in north Manchester, agrees. "Girls will tend to personalise issues," he says.
"This is something of a generalisation, but if you tell them off they are likely to say something like, 'You don't like me, do you?' And girls do misbehave - they just do it in a different way. They may be more deferential to authority, but misbehaviour is often more sneaky, manipulative and hard to uncover. They may appear to be well-behaved but may be pleasantly wasting time chatting."
Teachers at boys' schools may find that they spend a lot of time dealing with disciplinary issues, but those at girls' schools may be preoccupied with helping their students to resolve friendship breakdowns, boyfriend troubles and difficulties at home.
"Form tutors play a crucial role," says Ms Wybar. "They will often need to mediate in friendship problems or situations in which girls are deliberately excluding other girls.
"With boys, trouble can blow up in a matter of minutes, so teachers may need to be reactive - but with girls, trouble can be brewing for weeks or months, so teachers have to keep a close eye on what's happening and prevent problems where they can."
Another consideration is the gender dynamic between teacher and student.
Younger teachers - particularly men - can gain heart-throb status and can rival pin-ups such as David Beckham or Brad Pitt for students' attention.
In his previous job at a girls' school, Mr Fothergill received love letters, Valentine's cards and various gifts, including beer and wine. This might be flattering, but being on the receiving end of such attention can make teachers vulnerable.
"I was always careful to ensure I was never in a room alone with a student," he says. "But that itself isn't enough. At the end of a lesson, one girl came up to me and said, 'Sir, I can't keep it to myself any more - I want you.' Of course, I had to seek help from management to deal with that one."
Female teachers can also find themselves in a vulnerable position in a boys' school, where students may try to undermine and unnerve female staff.
"One boy came up to me in the corridor and made a very sexual remark," says Jo Graham, a newly qualified teacher who worked in a boys'
school in Kent during her teaching practice. "It was hugely embarrassing and it felt predatory. I've never forgotten the leer on his face and the laughter of the boys around him."
Such incidents are rare. Single-sex schools often provide support and training on gender issues. At Tunbridge Wells girls' grammar, experienced practitioners run training for young male staff on teaching the opposite sex. And, far from reducing your chances of getting a job at a mixed school in the future, a spell at a single-sex school can show prospective employers that you have a greater understanding of how students learn.
As Mrs Wybar puts it: "It's a steep learning curve, but it's a great way to sharpen your understanding of teaching and learning."